Numerical Study of Inner Heater Division and Rayleigh Bénard Convection in PCM Melting within an Annular Cavity

Maximizing heat transfer areas and optimizing heat source arrangements directly enhance heat transfer rates. In the current study, the influence of the inner tube’s heat transfer area and tube arrangements on the melting rate of Phase Change Material (PCM) contained inside a cylindrical container and subjected to Rayleigh-Benard convection is numerically investigated. COMSOL Multiphysics software and the finite element approach were employed for obtaining the numerical solution of the governing equations. Four different cases, depending on the shape and arrangement of the inner tubes, were considered. The first case is a conventional cylinder; the second and third cases contain two mid-cylinders vertically and horizontally mounted, respectively. While four quarter-cylinders present case four. The results indicated that the melting time was 8000 s, 6800 s, 5000 s, and 4300 s for cases A, B, C, and D, respectively. In comparison with the conventional cylinder, case four reduced the melting time by 46.25% and stored 15% more energy.